Hybrid airship with a flexible compartmented exterior envelope

ABSTRACT

A hybrid airship has both aerostatic and aerodynamic lift comprising: an engine, a flexible external envelope ( 2 ) and at least one primary enclosure Ep filled with lifting gas (G). The primary enclosure Ep having an elastic wall P 1  separating this enclosure from compartment C 1 , the latter having an elastic wall P 1  separating compartment C 1  from compartment C i , the latter having an elastic wall P i+1  separating the compartment C i  from compartment C i+1 , and so on up until elastic wall P J+1  separating compartment C J  from compartment C J+1  where J corresponds to a whole number greater than or equal to 1, each compartment C i  being equally delimited by the flexible exterior envelope. The hybrid airship includes a) a valve V i  between each compartment C i  and its adjacent compartment C i+1 , and b) a controller ( 22 ) for the valve V i .

FIELD OF INVENTION

The present invention relates to the airship domain, particularly that of a hybrid airship providing aerostatic lift and aerodynamic lift, and capable of transporting a useful payload.

DISCUSSION OF PRIOR ART

Prior art essentially deals with airships providing aerostatic lift and in which the lift depends on the volume of a light gas carried on-board, as well as its degree of compression. The light gas is known as the lifting gas.

With this type of airship, the variation in altitude is effected by controlling the level of compression of the volume of the light gas, often helium. The greater the compression, the less lift is produced.

This principle is described for example in document WO2013/041820. However, this type of solution requires a compressor and a great deal of energy in order to vary the level of compression of the helium volume.

SUMMARY OF THE INVENTION

To overcome at least in part these disadvantages, the object of the present invention is a hybrid airship providing aerostatic lift and aerodynamic lift, and comprising:

-   -   a means of propulsion     -   a flexible exterior envelope     -   at least one primary enclosure filled with a lifting gas, said         primary enclosure Ep having an elastic wall P₁ separating this         enclosure from a compartment C₁, the latter having an elastic         wall P₁ separating compartment C₁ from compartment C_(i), the         latter too having an elastic wall P_(i+1) separating compartment         C_(i) from compartment C_(i+1), and so on up until an elastic         wall P_(J+1) separating compartment C_(J) from compartment         C_(J+1) where J corresponds to a whole number greater than or         equal to 1, each compartment C_(i) being equally bounded by the         exterior flexible envelope;     -   a means of communication V₁ between each compartment C_(i) and         its adjacent compartment C_(i+1);     -   a means of control of the means of communication V_(i);

said means of control being configured so as to:

(a) during an ascent phase with the lifting gas retained by one of the walls P_(i) with i anywhere between 1 and J, it maintains the means of communication V_(i) in a closed configuration so that the lifting gas, expanding with the altitude, exercises on wall P_(i) a pressure capable of producing an elastic deformation of wall P₁ from its nominal position to a maximum deformation position in which it flattens against wall P_(i+1) and reduces the volume of compartment C_(i) substantially to zero, by the evacuation of the air initially occupying this said compartment C_(i);

(b) then when wall P_(i) is in a position of maximum deformation, to open the means of communication V_(i) in such a way that wall P_(i) returns to its nominal position, by an automatic re-balancing of the pressure of the lifting gas on both sides of this wall P_(i);

(c) then, where appropriate, during continuation of the ascent phase and after the return of wall P_(i) to its nominal position, to repeat actions (a) and (b) for wall P_(i+1) as many times as necessary and as long as i remains less than or equal to J.

The invention thus has the characteristic of combining aerostatic lift with aerodynamic lift. Due to the aerodynamic lift, it is no longer necessary to act upon the compression of the lifting gas to control the altitude of this hybrid airship. The proposed solution permits, an astute management of the expansion phenomenon of the lifting gas with altitude, by providing a design having several compartments into which the lifting gas can progressively penetrate one by one, during the ascent phase of the airship.

Consequently, the airship does not require a lifting gas compressor as in prior art, and the means of propulsion employed are less energy-intensive than this type of compressor.

Moreover, being essentially constructed of flexible elements, it is less bulky when on the ground, when emptied of its air and lifting gas. This provides ease of transport of the airship. It makes the airship lighter in relation to classical rigid or semi-rigid designs, this permits limiting the dimensions of the airship.

Furthermore, thanks to its multi-compartmentalization, the hybrid airship according to the invention confers increased security since in case of damage to one of its compartments, the others continue to ensure minimum lift.

Finally, the multi-compartmentalization permits easy adaptation of the quantity of on-board lifting gas to the characteristics of the intended flight, by filling on the ground an appropriate number of compartments. This number of compartments filled with lifting gas can thus vary depending on the flight schedule, and in relation to the needs of each mission.

The invention also has the following optional characteristics, either singly or in combination.

Said means of propulsion include one or more engines, preferentially mounted on pivots along the transversal axis of the hybrid airship. This permits changing the angle of incidence of the airship and equally the lateral control of the latter by applying different pivoting movements to the engines located either side of the median plane. This lateral control can alternatively, or simultaneously, be effected by applying different rotation speeds to the engines.

Said flexible exterior envelope forms a wing or two semi-wings, whose shape is maintained at least in part by the air/lifting gas located in the primary enclosure and compartments C_(i).

Said primary enclosure is centered in the airship and a series of compartments C_(i) extend either side of the primary enclosure, in a transversal direction of the airship.

In this case, the two series of compartments C_(i) are constructed symmetrically in relation to the symmetrical plane of the airship.

According to a first preferred embodiment of the invention, the means of communication V_(i) comprise, for each elastic wall P_(i), an associated electrovalve built into elastic wall P_(i).

The airship also comprises an air exit electrovalve associated with compartment C_(J+1), and configured to stop/allow communication of air between compartment C_(J+1) and the exterior of the airship.

In the first preferred embodiment of the invention, said means of control are configured so that during the ascent phase, with the means of communication V_(i) in a closed configuration so that the lifting gas exerts on wall P_(i) a pressure capable of exerting an elastic deformation of wall P_(i), the means of communication V_(i+1) to V_(J+1) as well as said electrovalve is maintained in an open configuration. This permits the evacuation of the air by the latter compartment V_(J+1), during the expansion of the lifting gas. In this regard, given that the pressure of the interior of the airship must be slightly superior to the external pressure in order to maintain its aerodynamic shape, the open configuration of the communication means must be modulated to retain such slight internal pressure.

In a second preferred embodiment, the hybrid airship comprises a fluid conduit on the exterior of the airship, and a means of communication V_(i), for each elastic wall P_(i) from i ranging to 1 to J+1:

-   -   an intermediate electrovalve V_(int i) mounted on the fluid         conduit;         -   an electrovalve V′_(i−1) on one side connected upstream of             the intermediate electrovalve V_(int i) in relation to the             direction of flow to the exterior of the airship, and on the             other side communicating with compartment C_(i−1) or the             primary enclosure for i=1; and     -   an electrovalve V′_(i) on one side connected downstream of the         intermediate electrovalve V_(int i) in relation to a direction         of flow towards the exterior of the airship, and on the other         side communicating with compartment C_(i).

In this second preferred embodiment, said means of control are configured so that during the ascent phase, the maintaining in closed configuration of the means of communication V_(i), controlled so that the lifting gas exerts on wall P_(i) a pressure capable of producing an elastic deformation of wall P_(i), is ensured by maintaining in closed configuration said electrovalve V′_(i−1) and/or said intermediate electrovalve V_(int i), and by maintaining said electrovalve V′_(i) in an open configuration. This permits the air contained in compartment C_(i) to escape via electrovalve V′_(i) in direction of the fluid conduit, in order to be extracted from the airship.

Said means of control are then preferably configured so that in an ascent phase, with the means of communication V_(i) in a closed configuration so that the lifting gas exerts on wall P_(i) a pressure capable of exerting an elastic deformation on wall P_(i), the intermediate electrovalve V_(int i+1) to V_(int J+1) being maintained in open configuration.

Here equally, the open configurations of the means of communication must be modulated to retain a slight overpressure inside the airship.

Whatever the implementation envisaged, the hybrid airship preferably comprises a means of introducing air into compartment C_(J+1), during the descent phase of the hybrid airship, and during which the lifting gas shrinks with the loss of altitude.

Said flexible exterior envelope is manufactured in a less flexible material than that of said elastic walls, the latter being preferentially an elastomer material.

The invention finally has as object a hybrid airship control procedure as described above, and implemented so that:

(a) during an ascent phase with the lifting gas retained by one of the walls P_(i) with i anywhere between 1 and J, the means of communication V_(i) are maintained closed so that the lifting gas, expanding with the altitude, exerts on wall P_(i) a pressure producing an elastic deformation of wall P_(i) from a nominal position to a maximum deformation position in which it flattens against wall P_(i+1) reducing the volume of compartment C_(i) substantially to zero, thanks to the evacuation of the air initially occupying this compartment C_(i);

(b) then when wall P_(i) is in the position of maximum deformation, the means of communication V_(i) are opened so that wall P_(i) returns to its nominal position, via an automatic rebalancing of the pressures of the lifting gas on either side of this wall P_(i);

(c) then, as necessary, during the continuation of the ascent phase and after return of wall P_(i) to its nominal position, the actions (a) and (b) are repeated for wall P_(i+1) as many times as necessary as long as i remains less than or equal to J.

Other advantages and characteristics of the invention will appear in the detailed and non-limitative description given below.

BRIEF OF DESCRIPTION OF THE DRAWINGS

This description relates to the drawings in the Appendix and in which:

FIG. 1 shows a perspective view of a hybrid airship according to the preferred embodiment of the invention;

FIG. 2 shows a perspective view of a hybrid airship in an alternative embodiment;

FIG. 3 shows a diagram of part of the hybrid airship shown in FIG. 1, in cross-section along the length of line III-III in FIG. 1;

FIGS. 4a to 4h show the principle of the invention in which compartments of the airship fill with lifting gas, during the ascent phase of the airship;

FIGS. 5a to 5f show the principle of the invention in which the compartments of the airship empty one after another of lifting gas, during the descent phase of the airship;

FIGS. 6a to 6h show similar views to those of FIGS. 4a to 4h , with the airship in the second preferred embodiment; and

FIGS. 7a to 7f show views similar to those of FIGS. 5a to 5f , with the airship in the second preferred embodiment.

DETAIL DESCRIPTION OF PREFERRED EMBODIMENTS

In FIG. 1 is shown a hybrid airship according to the first preferred embodiment of the invention. The airship has a flexible external envelope 2 defining one or more aerodynamic surfaces, here with two semi-wings 4 located either side of the central part 6 of the airship which extends along longitudinal axis 8.

In this first preferred embodiment, an engine 10 is mounted at the end of each semi-wing 4. Alternatively, these engines could be mounted at the rear or front of the hybrid airship. Each engine 10 pivots on transversal axis 12 of the airship, this axis 12 being orthogonal to axis 8 and preferably corresponding to the pitch axis of the airship. In an alternative embodiment shown in FIG. 2, the flexible external envelope 2 forms a single wing, still with engines 10 mounted laterally, forwards or at the rear.

Thanks to the pivoting of engines 10, the airship can easily change angle to descend or ascend to the desired altitude. Moreover, the pivoting can be extended into a vertical position, during take-off or landing phases.

The lateral control of the airship 1 can be effected by varying the speed of rotation of the two engines 10, and/or by varying their pivoting around axis 12.

In the first embodiment, the airship 1 does not comprise a mobile aerodynamic element, such as a leading edge mobile flap, or similar. Nevertheless, this type of element could be implemented, without departing from the framework of the invention. The aerodynamic lift sought with airship 1 according to the first preferred embodiment is thus obtained thanks to the semi-wings 4 and engines 10 of variable inclination.

However, the hybrid character of airship 1 results from the fact that its lift is not only aerodynamic but also aerostatic, thanks to the volume of lifting gas on-board, for example helium.

It shall be noted that the proportion of aerostatic and aerodynamic lift is spread in relation to the useful payload carried, as well as the service ceiling of the airship's mission. Ideally, the proportion of aerostatic lift tends to balance the weight of the empty structure. In fact, it is interesting to retain an aerostatic lift slightly inferior to the weight of the empty structure, i.e., without a useful payload, in order to avoid difficulties such as a spontaneous take-off of the airship during the ground phases of loading/unloading. Thus, engines 10 essentially serve to lift the useful payload, but also provide forward movement and steering, as described above.

FIG. 3 shows one of the two semi-wings 4 of the airship, it being understood that the other wing is produced in a symmetrical manner, in relation to the vertical and longitudinal median plane P′ of the airship, and according to the symmetrical plane of the airship. Plane P′ traverses the central part 6, that houses the primary enclosure Ep filled with lifting gas G. On either side of this primary enclosure Ep, are respectively two series of compartments C_(i), the two series forming the semi-wings 4 and being symmetrically arranged in the median plane P′.

Each series thus comprises several successive compartments according to the direction of the wingspan, the direction of span corresponding to the transversal direction of the airship and represented by arrow 20. In the direction of the wingspan 20 from the center outwards, is thus successively foreseen the primary enclosure Ep then compartments C₁, C_(i), C_(i+1), C_(J) and C_(J+1), where the number J corresponds to a whole number greater than or equal to 1. Similar to the primary enclosure Ep, each compartment is bounded at top and bottom by the flexible exterior envelope. Laterally, these same compartments are delineated by elastic walls preferably made from an elastomer material, more flexible than the material used for the exterior envelope 2. Furthermore, each compartment preferably extends the whole width of the wing, according to longitudinal axis 8.

More precisely, primary enclosure Ep is bounded by an elastic wall P₁ separating this enclosure from compartment C₁. The latter possesses an elastic wall P_(i) separating compartment C₁ from compartment C_(i). In a similar manner, compartment C_(i) possesses an elastic wall P_(i+1) separating compartment C_(i) from compartment C_(i+1), and so on up until elastic wall P_(J+1) separating compartment C_(J) from compartment C_(J+1). As previously stated, J is greater than or equal to 1, but the total number of compartments is preferably greater than 2, for example between 2 and 15. It will be apparent, that each elastic wall must be sufficiently deformable in order to be able to flatten against the directly adjacent walls. Consequently, the total number of compartments particularly depends on the maximum elastic extension of the selected material to form these walls in the form of membranes. It equally depends on the nature of the flight of the hybrid airship since if the missions envisaged include small or large variations in altitude, the number of compartments should be respectively reduced or increased. In fact, the lifting gas G is required to successively penetrate the different compartments and accompany its expansion with altitude, without being released into the atmosphere.

The hybrid airship comprises a means of communication V_(i) between each compartment C_(i) and its adjacent compartment C_(i+1). In this first preferred embodiment, the means of communication V_(i) is incorporated into the associated elastic walls P_(i), and preferably takes the form of an electrovalve. Moreover, an air exit valve V_(ext) is associated with compartment C_(J+1), this electrovalve being configured to authorise/stop the communication of air between compartment C_(J+1) and the exterior of the airship.

The ensemble of these electrovalves V_(i), V_(ext) are commanded by means of control 22 on-board the airship, or permitting a remote control of the airship.

In a ground moored state as shown in FIG. 3, lifting gas G has a reduced volume confined in primary enclosure Ep, while the compartments are filled with air. In the case of a flight at low altitude during which the expansion of the lifting gas shall be measured, the lifting gas G may equally be introduced into several compartments adjacent to the primary enclosure Ep, with the aim of increasing the aerostatic lift. In any case, whether moored on the ground or in flight, the shape of the semi-wings are maintained in part by air and the lifting gas filling their compartments as well as that of the primary enclosure. Moreover, the shape and arrangement of the compartments are such that the forces on the elastic walls, issuing from differences in pressure between the compartments, are balanced by the tension of the exterior flexible envelope issuing from external aerodynamic pressure and the internal pressure air or lifting gas, and by the forces generated by the flexing of the wing.

Finally, the hybrid airship comprises a means 24 for the introduction of air into compartment C_(J+1), useful during the descent phase of the hybrid airship when the lifting gas shrinks with the loss of altitude. Means 24 may take the form of a simple low power pump, or an air circuit taking and conducting exterior air under pressure, for example with the aid of a scoop system. The intake of air under pressure may be carried out downstream of the thrust generated by the engines.

Now shall be described the operating principle of the invention in relation to FIG. 3. More specific examples will be provided later for the other Figures.

One of the characteristics of the invention is the management of the ascent phase of the airship, during which control means 22 are configured in the following way:

(a) when lifting gas G is retained by one of the walls P_(i), the means of communication V_(i) are maintained closed so that the lifting gas, expanding with altitude, exerts on wall P_(i) a pressure capable of producing an elastic deformation of wall P_(i) from a nominal position to a maximum deformation position in which it flattens itself against wall P_(i+1) reducing the volume of compartment C_(i) substantially to zero, via an evacuation of the air initially in this compartment C_(i);

(b) when wall P_(i) is in a position of maximum deformation, the means of communication V_(i) is opened so that wall P_(i) resumes its nominal position, via an automatic rebalancing of the pressure of the lifting gas on either side of wall P_(i);

(c) then, as necessary, during continuation of the ascent phase and after return of wall P_(i) to its nominal position, actions (a) and (b) are repeated for wall P_(i+1) as many times as necessary as long as i remains less than or equal to J.

In this manner, the invention astutely accompanies the increasing volume of the lifting gas, resulting from its expansion caused by an ascent in altitude. A somewhat similar reverse principle accompanies the shrinking of the lifting gas during the descent phases, as shall be described hereafter with specific examples.

First, in reference to FIGS. 4a to 4h , the internal behaviour of the wing is shown during an ascent phase from the ground. This example is based on the first preferred embodiment of the invention. In an arbitrary manner, and with the aim of limiting the length of the descriptions, the number of compartments is limited to four, which corresponds to said number J equaling 3.

The ground moored configuration is shown in FIG. 4a , whereby four compartments C₁ to C₄ are filled with air, and the primary enclosure Ep is filled with lifting gas G. All the elastic walls P₁ to P₄ are in nominal, i.e. not or little deformed, and having a largely vertical flat shape.

When the ascent phase begins, the electrovalves V₂ to V₄ are maintained in an open configuration, as is the air exit electrovalve V_(ext) as shown in FIG. 4b . Only electrovalve V₁ is maintained in a closed configuration, so that under the effect of expansion of lifting gas G in the primary enclosure Ep, wall P₁ which delimits this enclosure is elastically deformed until reaching its maximum deformation shown in FIG. 4 b. In this position of maximum deformation, wall P₁ flattens itself against the exterior envelope 2 and against elastic wall P₂, in such a way that compartment C₁ is substantially reduced to zero. This is made possible by the evacuation of the air contained in compartment C₁, this air being forced towards compartment C₂ by electrovalve V₂ being open. Nevertheless, a slight overpressure is retained to ensure the aerodynamic shape, but this is limited and controlled. All the electrovalves located downstream are open and thus permit the air to transit via compartment C₃ then via compartment C₄, before being expelled from the wing into the atmosphere. The movement of the air is shown by the arrows in FIG. 4 b.

When wall P₁ is in its position of maximum deformation, electrovalve V₂ is tripped to a closed configuration while electrovalve V_(i) is reopened. Wall P₁ then returns to its nominal position as shown in FIG. 4c , via automatic rebalancing of the pressures of lifting gas G on either side of wall P₁.

Then, as the ascent phase continues, electrovalves V₃ and V₄ are in an open configuration, as is air exit electrovalve V_(ext) and electrovalve V_(i), as shown in FIG. 4d . Only electrovalve V₂ is maintained in closed, so that under the effect of expansion of lifting gas G in compartment C₁, wall P₂ that delimits this compartment elastically deforms until its maximum deformation position as shown in FIG. 4d . In this position of maximum deformation, wall P₂ flattens itself against the exterior envelope 2 and against elastic wall P₃, in such a way that compartment C₂ is substantially reduced to zero. This is made possible by the evacuation of the air contained in compartment C₂, this air being forced towards compartment C₃ by the open electrovalve V₃. Nevertheless, a slight overpressure is retained to ensure the aerodynamic shape, but this is limited and controlled. All electrovalves located downstream are open and thus permit the air to transit via compartment C₄, before being expulsed outside the wing into the atmosphere. The movement of the air is shown by the arrows in FIG. 4d . In this Figure, elastic wall P₁ has been shown in its nominal non-deformed position. However, in reality, it may undergo slight deformation produced by lifting gas G in the primary enclosure Ep, even if it communicates with compartment C₁ via open electrovalve V₁.

When wall P₂ is in its position of maximum deformation, electrovalve V₃ is tripped to a closed configuration while electrovalve V₂ is reopened. Wall P₂ then returns to its nominal position as shown in 4 e, via automatic rebalancing of the pressure of lifting gas G on either side of wall P₂.

During continuation of the ascent phase, electrovalve V₄ in an open configuration, as is the air exit electrovalve V_(ext) and electrovalves V₁ and V₂, as shown in FIG. 4f . Only electrovalve V₃ is maintained closed, so that under the effect of the expansion of lifting gas G in compartment C₂, wall P₃ that delimits this compartment elastically deforms until the maximum deformation position shown in FIG. 4e . In this position of maximum deformation, wall P₃ flattens itself against the exterior envelope 2 and against elastic wall P₄, in such a way that compartment C₃ is substantially reduced to zero. This is made possible by the evacuation of the air contained in compartment C₃, this air being forced towards compartment C₄ by open electrovalve V₄. Nevertheless, a slight overpressure is retained to ensure the aerodynamic form, but this is limited and controlled. The air can thus be expulsed outside the wing into the atmosphere. The movement of the air is shown by the arrows in FIG. 4f . In this Figure, elastic walls P₁ and P₂ have been shown in their nominal non-deformed position. However, in reality they may undergo slight deformation due to lifting gas G in primary enclosure Ep and in the first compartment C₁.

When wall P₃ is in its position of maximum deformation, electrovalve V₄ is tripped to a closed configuration while electrovalve V₃ is reopened. Wall P₂ then returns to its nominal position as shown in FIG. 4g , via automatic rebalancing of the pressure of lifting gas G on either side of wall P₃.

At the end of the ascent phase, the air exit electrovalve V_(ext) is in an open configuration, as are electrovalves V₁ to V₃, as shown in FIG. 4h . Only electrovalve V₄ is maintained closed, so that under the effect of the expansion of lifting gas G in compartment C₃, wall P₄ that delimits this compartment elastically deforms to the maximum deformation position shown in FIG. 4h . In this position of maximum deformation, wall P₃ flattens itself against the exterior envelope 2, in such a way that the volume of compartment C₄ is substantially reduced to zero. This is made possible by the evacuation of the air contained in compartment C₄, this air in fact being expulsed outside the wing via air exit electrovalve V_(ext). The movement of the air is shown by the arrow in FIG. 4h . In this Figure, elastic walls P₁ to P₃ have been shown in their nominal non-deformed position. However, they may in reality undergo a slight deformation produced by lifting gas G in the primary enclosure Ep and in compartments C₁ and C₂.

Compartment C₄ is not intended to be filled by lifting gas, in order to avoid the mixing of lifting gas G and air. The descent phase following the previously described ascent phase is largely carried out in a reverse manner, being somewhat assisted by means 24 aiding in the introduction of air into compartment C₄. This descent phase will now be described in reference to FIGS. 5a to 5 f.

The electrovalves are in the same configurations as those in FIG. 4h , particularly electrovalve V₄ that adopts a closed configuration. Under the effect of the loss of altitude, the lifting gas G shrinks at the same time as the exterior air penetrates compartment C₄, via electrovalve V_(ext). This leads wall P₄ to return to its nominal position, then to deform in the reverse direction in the direction of wall P₃. Wall P₄ that delimits compartment C₃ elastically deforms up to a position of maximum reverse deformation as shown in FIG. 5a . In this position of maximum reverse deformation, wall P₄ flattens against exterior envelope 2 and wall P₃, in such a way that the volume of compartment C₃ is substantially reduced to zero. This is made possible by the introduction of exterior air into compartment C₄, via exit air electrovalve V_(ext). The movement of the air is shown by the arrow in FIG. 5 a.

When wall P₄ is in its maximum reverse deformation position, electrovalve V₃ is tripped to a closed configuration while electrovalve V₄ is reopened. Wall P₄ then returns to its nominal position as shown in 5 b, via automatic rebalancing of the air pressure on either side of this wall P₄. During this rebalancing, the air exit electrovalve V_(ext) may be in either an open or closed configuration.

As the descent continues, under the effect of the loss of altitude, lifting gas G shrinks at the same time as the exterior air penetrates compartment C₄ via electrovalve V_(ext), then into compartment C₃ via electrovalve V₄ in an open configuration. This leads wall P₃ to return to its nominal position, then to deform in the reverse direction in the direction of wall P₂. Wall P₃ which delimits compartment C₂ elastically deforms to its maximum reverse deformation position shown in FIG. 5c . In this position of maximum reverse deformation, wall P₃ flattens against exterior envelope 2 and wall P₂, in such a way that the volume of compartment C₂ is substantially reduced to zero. This is made possible by the introduction of exterior air into compartments C₄ and C₃, as shown by the arrows in FIG. 5 c.

When wall P₃ is in its maximum reverse deformation position, electrovalve V₂ is tripped to a closed configuration while electrovalve V₃ is reopened. Wall P₃ returns to is nominal position shown in FIG. 5d , via automatic rebalancing of the air pressure either side of wall P₃. During this rebalancing, air exit electrovalve V_(ext) may be either open or closed, as is the case with electrovalve V₄.

As the descent continues, under the effect of the loss of altitude lifting gas G shrinks as the exterior air penetrates into compartment C₄ via electrovalve V_(ext), then into compartments C₃ and C₂ via electrovalves V₄ and V₃ in an open configuration. This leads wall P₂ to return to its nominal position, then to deform in the reverse direction in the direction of wall P₁. Wall P₂ which delimits compartment C₁ elastically deforms until a maximum reverse deformation position as shown in FIG. 5e . In this position of maximum reverse deformation, wall P₂ flattens against exterior envelope 2 and wall P₁, in such a way that the volume of compartment C₁ is substantially reduced to zero. This is made possible by introduction of exterior air into compartments C₄, C₃, C₂, as shown by the arrows in FIG. 5 e.

When wall P₂ is in its maximum reverse deformation position, electrovalve V₁ is tripped to a closed configuration while electrovalve V₂ is reopened. Wall P₂ returns to its nominal position shown in FIG. 5f , via automatic rebalancing of the air pressure either side of wall P₂. During this rebalancing, exit air electrovalve V_(ext) can remain in either open or closed configuration, as may electrovalves V₃ and V₄.

FIGS. 6a to 6h demonstrate the principle of the invention during the ascent phase of the airship in the second preferred embodiment of the invention. This second embodiment differs from the first embodiment essentially by the design of its means of communication V₁, which are constructed exterior to the elastic walls.

In fact, a fluid conduit 30 is provided with one extremity close to the center sealed and the other extremity giving on to the external atmosphere. This conduit 30 is preferentially straight and oriented in the direction of the span 20.

In addition, means of communication V_(i) associated with each elastic wall are no longer simple electrovalves in the walls, but are formed by an ensemble of three electrovalve including:

-   -   an intermediate electrovalve V_(int), mounted on the fluid         conduit;     -   an electrovalve V′_(i−1) on one side connected upstream of the         intermediate electrovalve V_(int i) in relation to the direction         of flow to the exterior of the airship, and on the other side         communicating with compartment C_(i−1) or the primary enclosure         for i=1; and     -   an electrovalve V′_(i) on one side connected downstream of the         intermediate electrovalve V_(int i) in relation to a direction         of flow towards the exterior of the airship, and on the other         side communicating with compartment C_(i).

In other words, each electrovalve V′_(i) simultaneously belongs to means V_(i) as well as means V_(i+1).

In practice, in the specific example of FIGS. 6a to 6h comprising four compartments C₁ to C₄, the configuration when on the ground is that shown in FIG. 6a , in which compartments C₁ to C₄ are filled with air, and the primary enclosure Ep filled with lifting gas G. All the elastic walls P₁ to P₄ are in the nominal position, namely not deformed or little deformed, ideally adopting a flat vertical plane.

When the ascent phase begins, the intermediate electrovalves V_(int 2) to V_(int4) are open, as shown in FIG. 6b . Only means V_(i) are closed, by closure of electrovalve V′_(D) and intermediate electrovalve V_(int 1). Consequently, under the effect of expansion of the lifting gas G in the primary enclosure Ep, wall P₁ which delimits this enclosure elastically deforms until the maximum deformation position shown in FIG. 6b . In this position of maximum deformation, wall P₁ flattens itself against the exterior envelope 2 and against elastic wall P₂, in such a way that compartment C₁ is substantially reduced to zero. This is made possible by the evacuation of the air contained in compartment C₁, this air being forced towards fluid conduit 30 by open electrovalve V′₁. In FIG. 6b , the arrows show the expulsion of air out of compartment C₁ and conduit 30.

When wall P₁ is in its maximum deformation position, the intermediate electrovalve V_(int 2) is tripped to a closed configuration while electrovalves V′_(D) and V_(int 1) are reopened in order to trip the ensemble of means V₁ to an open configuration. Wall P₁ returns to its nominal position as shown in FIG. 6c , via automatic rebalancing of the pressure of lifting gas G on either side of wall P₁.

Then, as the ascent phase continues, intermediate electrovalves V_(int 3) and V_(int 4) remain open, as shown in FIG. 6d . Means V₁ are maintained open, and only means V₂ are maintained closed, by closure of intermediate electrovalve V_(int 2). Consequently, under the effect of expansion of lifting gas G in compartment C₁, wall P₂ that delimits this compartment elastically deforms to its maximum deformation position shown in FIG. 6d . In this position of maximum deformation, wall P₂ flattens itself against the exterior envelope 2 and against elastic wall P₃, in such a way that compartment C₂ is substantially reduced to zero. This is made possible by the evacuation of the air contained in compartment C₂, this air being forced towards fluid conduit 30 by open electrovalve V′₂. In FIG. 6d , the arrows show the expulsion of air from compartment C₂ and conduit 30.

When wall P₂ is in its maximum deformation position, intermediate electrovalve V_(int 3) is tripped to a closed configuration while intermediate electrovalve V_(int 2) is reopened to trip the ensemble of means V₂ into an open configuration. Wall P₁ returns to its nominal position as shown in FIG. 6e , by automatic rebalancing of the pressure of the lifting gas G on either side of this wall P₂.

As the ascent phase continues the intermediate electrovalve V_(int 4) remains open, as shown in FIG. 6f . Means V₁ and V₂ are maintained open and only means V₃ are maintained closed, by closure of the intermediate electrovalve V_(int 3). Consequently, under the effect of expansion of lifting gas G in compartment C₂, wall P₃ which delimits this compartment elastically deforms until its maximum deformation position shown in FIG. 6f . In this position of maximum deformation, wall P₃ flattens itself against the exterior envelope 2 and against elastic wall P₄, in such a way that compartment C₃ is substantially reduced to zero. This is made possible by the evacuation of the air contained in compartment C₃, this air being forced towards fluid conduit 30 by open electrovalve V′₃. In FIG. 6f , the arrows show the expulsion of air from compartment C₃ and conduit 30.

When wall P₃ is in the maximum deformation position, intermediate electrovalve V_(int 4) is tripped closed, while intermediate electrovalve V_(int) is reopened, in order to place the ensemble of means V₃ into an open configuration. Wall P₃ then returns to its nominal position as shown in FIG. 6g , via automatic rebalancing of the pressure of lifting gas G on either side of wall P₃.

During the end of the ascent phase, means V₁ to V₃ are maintained in an open configuration as shown in FIG. 6h . Only means V₄ are maintained closed, by the closing of intermediate electrovalve V_(int 4). Consequently, under the effect of the expansion of lifting gas G in compartment C₃, wall P₄ that delimits this compartment elastically deforms until its maximum deformation position shown in FIG. 6h . In this position of maximum deformation, wall P₄ flattens itself against the exterior envelope 2, in such a way that the volume of compartment C₄ is substantially reduced to zero. This is made possible by the evacuation of the air contained in compartment C₄, this air being forced towards fluid conduit 30 by open electrovalve V′₄. In FIG. 6h , the arrows show the expulsion of the air from compartment C₄ and conduit 30.

In this second preferred embodiment of the invention, compartment C₄ is no longer intended to be filled by the lifting gas, in order to avoid mixing lifting gas G and the air. In fact, the descent phase following the ascent phase previously described, is carried out in a largely reverse manner, being assisted as necessary by means 24 aiding the introduction of air into the different compartments. This descent phase shall now be described in reference to FIGS. 7a to 7 f.

The means of communication V₁ are in the same configuration as those in FIG. 6h , and particularly means V₄ which adopts a closed configuration by closing of electrovalve V_(int 4).

Under the effect of the loss of altitude, lifting gas G shrinks at the same time as the exterior air penetrates compartment C₄, via the open electrovalve V′₄, being where necessary assisted by means 24 aiding in the introduction of air into compartment C₄. This leads wall P₄ to return to its nominal position, then to deform in the reverse direction in the direction of wall P₃. Wall P₄ which delimits compartment C₃ elastically deforms up to a position of maximum reverse deformation as shown in FIG. 7a . In this position of maximum reverse deformation, wall P₄ flattens against exterior envelope 2 and wall P₃, in such a way that the volume of compartment C₃ is substantially reduced to zero. This is rendered possible by the introduction of exterior air into compartment C₄, via electrovalve V′₄. The movement of the air is shown by the arrow in FIG. 7 a.

When wall P₄ is in the maximum reverse deformation position, intermediate electrovalve V_(int 3) is tripped into a closed configuration, whilst means V₄ are tripped into an open configuration by the opening of intermediate electrovalve V_(int 4). Wall P₄ returns to its nominal position as shown in FIG. 7b , via automatic rebalancing of the air pressure on either side of wall P₄. During this rebalancing, the means V₁ and V₂ are preferably in an open configuration.

As the descent continues, lifting gas G shrinks as the exterior air penetrates into compartment C₃, via open electrovalve V′₃. This leads wall P₃ to return to its nominal position, then to deform in the reverse direction in the direction of wall P₂. Wall P₃ which delimits compartment C₂ elastically deforms until its maximum reverse deformation position shown in FIG. 7c . In this position of maximum reverse deformation, wall P₃ flattens against exterior envelope 2 and wall P₂, in such a way that the volume of compartment C₂ is substantially reduced to zero. This is made possible by the introduction of exterior air into compartment C₃, via electrovalve V′₃. The movement of the air is shown by the arrows in FIG. 7 c.

When wall P₃ is in the maximum reverse deformation position intermediate electrovalve V_(int 2) is tripped into a closed configuration whilst means V₃ are tripped into an open configuration, by the opening of intermediate valve V_(int 3). Wall P₃ returns to its nominal position as shown in FIG. 7d , via the automatic rebalancing of air pressure on either side of wall P₃. During this rebalancing, means V₁ is preferably in an open configuration.

At the end of the descent, the lifting gas G shrinks as the exterior air penetrates into compartment C₂, via open electrovalve V′₂. This leads wall P₂ to return to its nominal position, then to deform in the reverse direction in the direction of wall P₁. Wall P₂ which delimits compartment C₁ elastically deforms until its maximum reverse deformation shown in FIG. 7e . In this position of maximum reverse deformation, wall P₂ flattens against exterior envelope 2 and wall P₁, in such a way that the volume of compartment C₁ is substantially reduced to zero. This is made possible by the introduction of exterior air into compartment C₂, via electrovalve V′₂. The movement of the air is shown by the arrows in FIG. 7 e.

When wall P₂ is in the maximum reverse deformation position intermediate electrovalve V_(int 1) is tripped into a closed configuration whilst means V₂ are tripped into an open configuration, by the opening of intermediate valve V_(int 2). Wall P₂ then returns to its nominal position shown in FIG. 7f , via automatic rebalancing of air pressure on either side of wall P₂.

Of course, various modifications may be made to the invention by one skilled in the art, and which is described here using non-limitative examples. 

1. A hybrid airship (1) having aerostatic and aerodynamic lift including: a means of propulsion (10); a flexible external envelope (2); at least one primary enclosure Ep filled with lifting gas (G), said primary enclosure Ep having an elastic wall P₁ separating this enclosure from compartment C₁, the latter having an elastic wall P_(i) separating compartment C₁ from compartment C_(i), the latter having an elastic wall P_(i+1) separating the compartment C_(i) from compartment C_(i+1), and so on up until elastic wall P_(J+1) separating compartment C_(J) from compartment C_(J+1) where J corresponds to a whole number greater than or equal to 1, each compartment C_(i) being equally delimited by the flexible exterior envelope; a means of communication V_(i) between each compartment C_(i) and its adjacent compartment C_(i+1); a means of control (22) and means of communication V_(i); said means of control (22) being configured so as: (a) during an ascent phase with lifting gas (G) retained by one of the walls P_(i) with i being between 1 and J, to maintain the means of communication V_(i) in a closed configuration so that the lifting gas, expanding with the altitude, exerts on wall P_(i) a pressure capable of producing an elastic deformation of wall P_(i) from a nominal position to a maximum deformation position in which it flattens itself against wall P_(i+1) by reducing the volume of compartment C_(i) substantially to zero, due to an evacuation of the air initially occupying compartment C_(i); (b) then when wall P_(i) is in the position of maximum deformation, to open the means of communication V_(i) in such a way that wall P_(i) returns to its nominal position, by automatic re-balancing of the pressure of the lifting gas on both sides of this wall P_(i); (c) then where appropriate, during continuation of the ascent phase and after the return of wall P_(i) to nominal position, to repeat actions (a) and (b) for wall P_(i+1) as many times as necessary as long as i remains less than or equal to J.
 2. A hybrid airship according to claim 1, characterised by said means of propulsion comprising one or more engines (10), preferably mounted on pivots in the transversal axis (12) of the hybrid airship.
 3. A hybrid airship according to claim 1, characterised by said flexible external envelope (2) forming a wing or two semi-wings (4), whose shape is maintained at least in part by the air/lifting gas located in the primary enclosure Ep and compartments C_(i).
 4. A hybrid airship according to claim 1, characterised in that said primary enclosure Ep is constructed in the center of the airship, and that a series of compartments C_(i) extend either side of the primary enclosure, in a transversal direction (20) of the airship.
 5. A hybrid airship according to the previous claim, characterised in that the two series of compartments C_(i) are arranged symmetrically in relation to the symmetrical plane (P′) of the airship.
 6. A hybrid airship according to claim 1, characterised in that the means of communication V_(i) comprise, for each elastic wall P_(i), an electrovalve built into the associated elastic wall P_(i).
 7. A hybrid airship, according to claim 1, characterised in that it equally comprises an air exit electrovalve V_(ext) associated with compartment C_(J+1), and configured so as to stop/authorise communication of air between compartment C_(J+1) and the exterior of the airship.
 8. A hybrid airship according to claim 1, characterised in that said means of control (22) are configured so that during an ascent phase, with means of communication V_(i) in a closed configuration so that the lifting gas (G) exerts on wall P_(i) a pressure capable of producing an elastic deformation of wall P_(i), said means of communication V_(i+1) to V_(J+1) as well as said air exit electrovalve V_(ext) are maintained in an open configuration.
 9. A hybrid airship according to claim 1, characterised in that it comprises a fluid conduit (30) leading to the exterior of the airship, and the means of communication V_(i) for each elastic wall P_(i) where i ranges from 1 to J+1: an intermediate electrovalve V_(int i) mounted on the fluid conduit (30); an electrovalve V′_(i−1) on one side connected upstream of the intermediate electrovalve V_(int i) in relation to the direction of flow to the exterior of the airship, and on the other side communicating with compartment C_(i−1) or the primary enclosure for i=1; and an electrovalve V′_(i) on one side connected downstream of the intermediate electrovalve V_(int i) in relation to a direction of flow towards the exterior of the airship, and on the other side communicating with compartment C_(i).
 10. A hybrid airship according to the previous claim, characterised in that said means of control (22) are configured so that during an ascent phase, the maintaining in a closed configuration of the means of communication V_(i), controlled so that the lifting gas (G) exerts on wall P_(i) a pressure capable of producing an elastic deformation of wall P_(i), is ensured by maintaining in a closed configuration said electrovalve V′_(i−1) and/or said intermediate electrovalve V_(int i), and by maintaining said electrovalve V′_(i) in an open configuration.
 11. A hybrid airship according to the previous claim, characterised in that said means of control (22) are configured so that during an ascent phase, with the means of communication V_(i) in a closed configuration so that the lifting gas exerts on wall P_(i) a pressure capable of producing an elastic deformation of wall P_(i), the intermediate electrovalves V_(int i+1) to V_(int J+1) are maintained in an open configuration.
 12. A hybrid airship according to claim 1, characterised in that it comprises means (24) of introducing air into compartment C_(J+1), during a descent phase of the hybrid airship during which lifting gas (G) shrinks with the loss of altitude.
 13. A hybrid airship according to claim 1, characterised in that said flexible exterior envelope (2) is manufactured from a material less flexible than that of said elastic walls.
 14. A hybrid airship according to claim 1, characterised in that said elastic walls are manufactured from an elastomer material.
 15. A control procedure for the hybrid airship (1) according to claim 1, characterised in that it is implemented so that: (a) during an ascent phase with the lifting gas retained by one of the walls P_(i) where i is between 1 and J, the means of communication V_(i) are maintained in a closed configuration so that the lifting gas (G), expanding with the altitude, exerts on wall P_(i) a pressure producing an elastic deformation of wall P_(i) from a nominal position to a maximum deformation position in that it flattens against wall P_(i+1) by reducing the volume of compartment C_(i) substantially to zero, via an evacuation of the air initially occupying this compartment C_(i); (b) then when wall P_(i) is in the maximum deformation position, the means of communication V_(i) are opened so that wall P_(i) returns to its nominal position nominal, via automatic rebalancing of the pressure of lifting gas (G) on either side of this wall P_(i); (c) then, as necessary, during the continuation of the ascent phase and after return of wall P_(i) to its nominal position, the actions (a) and (b) are repeated for wall P_(i+1) as many times as necessary as long as i remains less than or equal to J. 